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Solving the Puzzle of One‐Carbon Loss in Ripostatin Biosynthesis
Author(s) -
Fu Chengzhang,
Auerbach David,
Li Yanyan,
Scheid Ullrich,
Luxenburger Eva,
Garcia Ronald,
Irschik Herbert,
Müller Rolf
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201609950
Subject(s) - thiamine pyrophosphate , gene cluster , decarboxylation , polyketide synthase , biosynthesis , stereochemistry , biochemistry , polyketide , chemistry , acyltransferase , acyl carrier protein , gene , enzyme , cofactor , catalysis
Ripostatin is a promising antibiotic that inhibits RNA polymerase by binding to a novel binding site. In this study, the characterization of the biosynthetic gene cluster of ripostatin, which is a peculiar polyketide synthase (PKS) hybrid cluster encoding cis‐ and trans‐acyltransferase PKS genes, is reported. Moreover, an unprecedented mechanism for phenyl acetic acid formation and loading as a starter unit was discovered. This phenyl‐C2 unit is derived from phenylpyruvate (phenyl‐C3) and the mechanism described herein explains the mysterious loss of one carbon atom in ripostatin biosynthesis from the phenyl‐C3 precursor. Through in vitro reconstitution of the whole loading process, a pyruvate dehydrogenase like protein complex was revealed that performs thiamine pyrophosphate dependent decarboxylation of phenylpyruvate to form a phenylacetyl‐ S ‐acyl carrier protein species, which is supplied to the subsequent biosynthetic assembly line for chain extension to finally yield ripostatin.